1. Field of the Invention
This invention relates generally to metal plating and more particularly to improved an process for the uniform plating of microspheres for use in catalytic processes and electrical applications.
2.Description of Related Art
In U.S. Pat. No. 3,577,324, I described a process and apparatus for plating particles which had as a preferred embodiment the plating of polymeric beads formed from polystyrene cross-linked with divinyl benzene. A solution for bonding copper atoms to such beads was disclosed.
In U.S. Pat. No. 3,787,718, I disclosed the use of plated spherical particles as electronic components. In this patent the forming of additional coatings or platings on the copper layer was also disclosed.
U.S. Pat. No. 2,915,406, Rhoda et al., entitled "Palladium Plating by Chemical Reduction, discloses a number of baths for use in immersion plating of various metals.
The present invention discloses the preparation of resin microspheres having copper salts on the outer portion. These microspheres are separated into batches of substantially uniform sizes and are then plated. By plating microspheres of the same size and density (as determined by Stoke's law) a plating of uniform thickness can be achieved. This uniformly thick plating is essential when the plated microspheres are used in catalytic beds and/or with electric current flowing. Nonuniformly thick platings will result in hot spots which will cause the plating to spall off.